Question

我试图在我的add函数中按字母顺序排列两个单独的列表：一个按名字对节点进行排序，另一个按姓氏排序。我还有一些逻辑，检查名称是否已经在列表中，如果是错误，则打印错误并返回列表。就像标题所说的那样，我在这里遇到了分段错误，我不知道为什么。这可能是一个非常基本的问题，但我是C的新手，尤其是链接列表的新手。

以下是节点的定义方式：

typedef struct node {
    char *first;
    char *last;
    long number;
    struct node *nextFirst;
    struct node *nextLast;
} Node;

typedef struct mlist {
    Node *headFirstName;
    Node *headLastName;
} MultiLinkedList;

这是我的添加功能：

MultiLinkedList *add(MultiLinkedList *list, char *first, char *last, long num) {
    // allocate a new node
    Node *newNode = malloc ( sizeof(Node) );
    newNode->first = malloc ( strlen(first) + 1 );
    strcpy(newNode->first, first);
    newNode->last = malloc ( strlen(last) + 1 );
    strcpy(newNode->last, last);
    newNode->number = num;
    //make placeholder nodes
    Node *a = list->headFirstName;
    Node *b = list->headLastName;
    // add this new node at the head of the "byFirst" list
    if (strcmp(newNode->first, a->first) < 0) {
            newNode->nextFirst = list->headFirstName;
            list->headFirstName = newNode;
    }
    for (Node *i = list->headFirstName; i; i = i->nextFirst) {
            // add after less alphabetical nodes
            if (strcmp(newNode->first, i->first) > 0) {
                    newNode->nextFirst = i->nextFirst;
                    i->nextFirst = newNode;
            }
            // return error for duplicate name
            if (strcmp(newNode->first, i->first) == 0 && strcmp(newNode->last, i->last) == 0) {
                    printf("That person is already in the list! Please try with a different name.\n");
            }
    }
    // add this new node at the head of the "byLast" list
    if (strcmp(newNode->last, b->last) < 0) {
            newNode->nextLast = list->headLastName;
            list->headLastName = newNode;
    }
    for (Node *j = list->headLastName; j; j = j->nextLast) {
            // add after less alphabetical nodes
            if (strcmp(newNode->last, j->last) > 0) {
                    newNode->nextLast = j->nextLast;
                    j->nextLast = newNode;
            }
    }
    // return the multi-list object with updated or original head pointers
    return list;
}

Answer 1

我弄清楚我的问题是什么。我不得不在每个if语句的末尾添加return list;，否则函数会尝试执行每个真正的语句;这导致了seg故障。事后来看，我很惊讶我没有早点解决这个问题。

将节点插入链表期间的分段错误

1 个答案: